trig question (simple)
回答 (2)
2013-06-09 4:22 am
✔ 最佳答案
(1+cotx)(1-cotx)/2 -1=(1- cot^2 (x) -2) /2
=-(1+cot^2 (x)) /2
= -cosec^2 (x)/2
= -(1/sin^2 (x) /2)
= - (1/2sin^2 x)
=- 1/2a^2
Hope I can help you!!!
2013-06-08 12:36 am
圖片參考：http://i1096.photobucket.com/albums/g340/pingshek/2013-06-07_zps41f79fd0.png
http://i1096.photobucket.com/albums/g340/pingshek/2013-06-07_zps41f79fd0.png
參考: pingshek
收錄日期: 2021-04-30 17:15:15
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130607000051KK00140